Answer :
Well I'm assuming this is bedmas so you would do 14+__=80 divided by 4 and since there's no brackets you would do division first 14+__=20 and than you have to get the blank alone so you would do 20-14 which equals 6 so 14+6=80 divided by 4. You could also use an x to represent the blank. Also sometimes teachers want you to write 14-14+__=40-14 than __=40-14=26
Most want it written like this
14+__=80 divided by 4
14+__=20
14-14+__=20 (or __=20-14)
__=6
Than rewrite it: 14+6=80 divided by 2